Cardiac Cycle/Heart sounds Flashcards Preview

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Flashcards in Cardiac Cycle/Heart sounds Deck (22):


Closure of mitral and tricuspid valve

Loudest at apex



Closure of aortic/pulmonic


S1 split- causes


Delayed RV activaiton


Increased/decreased S1 intensity

Increased: short PR interval, mitral stenosis, tachycardia

Decreased: long PR interval, mitral regurg, severe mitral stenosis, stiff LV


What is physiological splitting?

Occurs with S2 upon inspiration due to delay of pulmonic valve closure bc more blood--> lungs


What can cause widened splitting of S2?

RBBB, pulmonic stenosis


Fixed splitting of S2

doesn't vary with resp = atrial septal defect


Paradoxical splitting of S2

Reverse pattern with resp

Due to LBBB, advanced aortic stenosis


What are examples of extra heart sounds?

Ejection click

Midsystolic/late click

Opening snap


S3 or S4 gallop


What causes an ejection click?

Abnormal valves --> abnormal valve closure or opening sounds

If heard after S1, it's when the aortic or pulmonic valve are abnormal (i.e. bicuspid aortic) or dialted


What causes a mid or late systolic click?

Due to systolic prolapse of mitral or tricuspid valve


What causes an opening snap?

A thickened mitral or tricuspid valve: high pitched, best heard between apex & left sternal border


What causes an S4 gallop?

End-diastolic sound (right before S1) that's generated by L or R atrium contracting against a stiffened ventricle

Best heard at apex or LLSB-- dull, low pitched sound

Usually indicates cardiac disease, may be normal in individuals over age 50 due to aging/stiffening of LV


What causes an S3 gallop?

Early diastolic sound that corresponds to early ventricular filling

Dull, low pitched, best heard with bell at the apex or LLSB

Normal in children/young adults

Indicates heart failure in adults

Note that opening snap and S3 are both early diastolic sounds but opening snap is high pitched & heard btw apex & LLSB whereas S3 is low pitched at heard at apex/LLSB


What causes a murmur?

Turbulent blood flow. Mechanisms:

1. Flow across a partial obstruction (stenotic valve)
2. Increased flow through normal structures (high output
states such as anemia or pregnancy)
3. Ejection into a dilated chamber (dilated aortic root)
4. Regurgitant flow across an incompetent valve
5. Abnormal shunting of blood from one vascular
chamber to a lower-pressure chamber (ventricular
septal defect, patent ductus).


What are the 3 main types of systolic murmurs:

Ejection type 


Late systolic 


What causes a systolic ejection murmur?

Aortic/pulmonic stenosis

**severity is greater if the peak of murmur is later


What causes a pansystolic/holosystolic murmur?

Mitral regurg, Tricuspid regurg, VSD



What causes late systolic murmurs?

Mitral valve prolapse


What causes diastolic murmurs?

Early decrescendo: regurgitant flow through aortic/pulmonic valve

Mid-to-late: turbulent flow through stenotic mitral/tricuspid valve or increaed flow accross a normal valve
*if it's stenosis, preceded by opening snap

Prolonged mid-to-late: severe mitral or tricuspid stenosis

Continuous: patent ductus arteriosus

To-and-fro: aortic/pulmonic stenosis & regurgitaiton


Locations of murmurs


Which heart sounds do you hear for the valvular diseases?

Aortic stenosis: S4, Harsh systolic ejection murmur, paradoxical splitting (Also: delayed carotid, reduced A2)

Aortic regurg: wide pulse pressure, blowing decrescendo diastolic murmur LLSB, low frequency diastolic rumble=Austin flint, displaced hyperdynamic LV impulse

Mitral stenosis: Increased S1, opening snap in early diastole, diastolic rumble with presystolic accentuation =murmur , signs of pulm htn (RV heave, increased P2)

Mitral regurg: holosystolic murmur at apex that worsens with fist clench, S3